Optical waveguides are used for many purposes including the transmission of optical signals and creation of resonators. Generally the waveguide can be configured in any number of patterns to achieve some predetermined goal. Examples include waveguides configured in closed loop configurations so as to create resonators, waveguides in linear configurations so as to comprise signal transmission mediums as well as waveguides configured to form y-splitters and optical couplers.
As previously mentioned optical waveguides can be configured in a closed loop to form an optical resonator. These optical resonators can then be used in rotation sensing devices. Within the closed loop resonator optical signals are caused to propagate around the closed loop in opposite directions. By measuring and/or combining these counterpropagating optical signs a rotation sensing device is realized.
A problem with all solid state rotation sensing devices is their sensitivity to changes in temperature. Changes in temperature have multiple affects on these solid state devices. Specifically, a change in temperature can cause physical expansion and/or contraction of the devices thus causing a change in the physical size of the waveguide. A change in temperature also affects the index of refraction of the dielectric material. Therefore changes in temperature have a dual affect on the optical waveguides.
Changes in physical size and optical index of refraction adversely affect the performance and operation of the optical waveguides. For use in rotation sensing, a waveguide configured as a ring resonator must be thermally stable since the resonant frequency must remain constant. Changes in resonant frequency due to effects other than rotation of the device adversely affects the operation of the rotation sensing device. Furthermore, since the optical signals which are being used to detect rotation are of a very high frequency, even small variations in size will affect the optical signals and subsequently reduce the accuracy and sensitivity of the rotation sensing device.